Social anxiety is frequently reported by individuals with ASD. If atypical eye gaze in ASD can not be fully explained by emotional models, a subgroup seems to present an active gaze avoidance associated with the report of social anxiety symptoms. The main objective of our study was to examine the gaze related anxiety in a population of adults with ASD compared with what's observed in adults with SAD. The purpose was to confirm the experience of social anxiety for some individuals with ASD and quantify its impact on gaze functioning. We included adult patients diagnosed with ASD without intellectual disability (n = 13) or SAD (n = 11) from three outpatient clinics. Patients were divided in two groups, ASD and SAD, and filled three clinical scales: Gaze Anxiety Rating Scale (GARS, Schneier et al., 2011), Liebowitz Social Anxiety Scale (LSAS, Liebowitz et al., 1999), and Social responsiveness Scale-2 (SRS-2, Constantino et al., 2003). Patients with ASD presented higher scores on SRS-2 (M [SD]: 73.5 [8.9] vs 52.4 [10.4]; P < 0.001) and lower on LSAS (M [SD]: 58.6 (32.1) vs 83.8 [22.8]; P < 0.05) but no difference on GARS scores compared to people with SAD. Furthermore, a sub-group of ASD patients, presenting with more social anxiety, reported greater gaze related anxiety and avoidance than other patients with ASD (M [SD]: 57.8 (20.5) vs 19.4 [23.5]; P < 0.05). Social anxiety can be present in ASD with an impact on gaze functioning. The SRS-2 and LSAS seem to be efficient differentiating anxiety from social ability deficits and maybe useful to guide patients toward a specialised evaluation.